Process of making calcium cyanamid by the action of nitrogen or calcium carbid.



making calcium cyanamid from calcium car- To all whom it may concern.

iiniann arenas a EMILIO GUI, OFROME, ITALY, ASSIGNOR TO THE FIRM OF IN G. BARZANO & ZANARDO,

OF ROME, ITALY.

PROCESS OF MAKING CALCIUM CYANAMID BY THE ACTIlJN 0-15 NITROGEN 0R CALCIU CARBID.

Specification of Letters Patent.

Patented Dec. 141, 19115.

No Drawing. Original application filed .April 17, 1913, Serial No. 761,719. Divided and this application 1 filed June 4, 1914. Serial No. 842,863.

Be it known that I, EMILIO GUI, a subjectof the King'of Italy, residing at Rome, Italy, "gentleman, (Whose post-office address is Via Lucrezio Caro No. 67,) have invented certain new and useful Improvements in Processes of Making Calcium Cyanamid by the Action of Nitrogen on Calcium Carbid, of which the following is a specification.

This invention relates to processes of bid and has for .its object to produce such calcium cyanamid, in a manner to be more fully disclosed below.

This applicationis a division of my copending application Number 761719, entitled Improvements in manufacturing calcium cyanamid by the action of nitrogen on calcium carbid an'd filed April 17th 1913.

It is known that calcium cyanamid is prepared by-reaction, obtained in suitable condition, of nitrogen on calcium carbid, andthat the product of this reaction is a compact mass which must be broken up and pulverized for being marketable. It is also known that the reaction between nitrogen and calcium carbid is very. exothermic. It

has been found by a series of experiments thatwhen heating a pulverized calcium .cyanamid the latter does not form again a compact mass even if the temperature to which 'it is heated is higher than "the temperature at which nitrogen enters into reaction with the carbid. It has also been found that when mixing with the pulverized calcium cyanamid very small quantities of pulverized calcium carbid and heating this mixture sufficiently in the presence of nitrogen, the latter reacts very well even on the particles of carbid distributed in the cyanamid already formed; in the latter case, however, if the quantity of carbid is small enough relatively-to the quantities ofcyanamid in which the said carbid is distributed,

the mixture of cyanam'id already formtd,

and also the newly formed cyanamid'do not form a compact mass, but, on the contrary the said mixture remains in a condition uofpowder or friable particles. On this notion a new process for manufacturing calcium cyanamid has been based by using a reaction chamber which is thermically i.n

sulated and subjected to a special moveticles.

ment. -After the temperature of the said ber after having been mixed, while still red hot, with the fresh charge of carbid,

whereupon the portion which had remained in the oven is taken out, and so forth. Ob-.

viously only a quantity of cyanamid corresponding to the charge of carbid may be extracted, and the remainder is left in the reaction chamber in which the mixture of carbid and'cyanamid is effected.

Owing to the fact that the reaction chamher is thermically insulated as much as possible, and the reaction between the nitro-- gen and carbid is very exothermic, when the reaction has begun in any way, it may proceed indefinitely by the heat produced by the reaction alone or with the addition of little outside heat. In fact, the calories which during one phase of the reaction process are absprbed by the walls of the reaction chamber and by the materials contained in the latter, are partially given back in a subsequent phasto the carbid of the fresh charge by the said walls and material, and thereby the carbid of the fresh charge is brought to the temperature necessary for the reaction. wConsequently an exchange of thermical energy takes place which forms the main feature of the present process, and a perfect utilization of the said energy is obtained.

Thereafter a portion of the said; contents is replaced into the reaction cham-' This movement, however, must be such that the said materials instead of being simply pushed from one end to the other of the chamber are, on the contrary n ixed rapidly, intimately and uniformly together. The heat stored in the reaction chamber is conther sequently distributed uniformly in all the parts of the oven, and the nitrification of 'carbid is effected more rapidly and com- 'inferior to that which must be reached in other known processes. All damages caused I by too high temperatures are thereby eliminated.

According to the degree of discontinuity with which the above described process is.

effected, and accondingto the quality of the raw carbid used (and consequently the number of calories developed by-its weight), it

may be necessary to supply the reaction. chamber with heat not produced by the reaction itself, not only-at the beginning for starting manufacturing, but also afterward in order to revivify the same.

Instead ofcalcium cyanamid one may mix with the carbid (in the relatively very high proportion necessary for carrying out the present process) one or more substances in a powdered condition which do not coagulate at the temperature of thereaction chamber, such substances being for instance carbon, lime, leucite and other silicates of this kind. As it is possible to make the said substitution, it is also possible to begin the manufacture of calcium cyanamid by the.

present process without starting with cyanamid prepared by a different process.

The above described process may be also efi'ected if the powdered carbid outside of the reaction chamber, and without being'in contact with the nitrogen, reaches so high a temperature that apartial scission of its molecules takes place. The said process is also effected if instead of pure nitrogen the same is used mixed with other gases which are indifi'erent or nearly indifferent to carbid and cyanamid in-the conditions of operation obtained in the process, which latter is also efiected if to the calcium carbid well known quantities of reaction exciting or accelerating substances are added, such as for instance cyanids, ferrocyanids or ferricyanids, halogenated oxids or salts of alkali and alkaline-earth metals, earth metals, and so forth. The said exciting or accelerating substances, however, may be added in very small proportions in the present process as in all other processes, because, owing to the movement and .subdivision of the materials contained in the reaction chamber, the said Copies of this patent may be obtained for .substances may subsequently be in contact,

with ever fresh carbid particles.

The red hot cyana-mld put again in the cycle of manufacture, must be, of course, protected, before being put in, against the action of atmospheric influences and losses of'heat.

Having now fully described my said invention and the manner in which the same is to be performed, what I claim and desire to secure by Letters Patent is:

1. A process of preparing calcium cyanamid, said process consisting in mixing asmall portion of calcium carbid with a large portion of red hot calcium cyanamid; and V passing nitrogen thereover whereby calcium cyanamid and heat are produced.

2. A process of preparing calcium cyana-mid said process consisting in mixing a small portion of calcium carbid with a large portion of red hot material containing cal- 4. A process of preparing calcium cyan' amid, said process consisting 1n mixing a small portion of calcium carbid with a large portion of red hot other material inthe form of powder; and passing nitrogen thereover.

5. A process for preparing calcium cyanamid, said process consisting in mixing asmall portion of calcium carbid with a large portion of red hot material containing cal-* cium cyanamid; passing nitrogen thereover whereby calcium cyanamid and heat are 105,

produced; adding additional small quantities of carbid; and extracting the formed cyanamid.

6. A process of preparing calcium cyanamid, said process consistlng in mixing a small portion of calcium carbid with a large portion of red hot other material inp0w dered condition and which does not fuse at the temperature used; and passing nitrogen thereover. 1 15 In testimony whereof I have signed my name to this specification in presence of two subscribing witnesses.

I EMILIO GUI.

Witnesses DUILID NARDONI, Mmo VIVENsY.

five cents each, by addressing the Commissioner of Eatent, Washington, D. 0. 

